The invention concerns an electric motor-actuated linear drive, in particular for adjusting moveably mounted parts of lying and seating furniture, including for the medical sector like rehabilitation organizations, care beds, etc. The drive comprises a drive motor, a threaded spindle, a speed reduction gear arranged between the drive motor and the threaded spindle, a spindle nut which is carried on the threaded spindle and which can be selectively arrested in the direction of rotation and which is displaceable in the axial direction of the threaded spindle in dependence on the direction of rotation of the threaded spindle, and a stroke element drivable by the axial movement of the spindle nut for adjusting the moveable furniture parts.
Such an electric motor-actuated linear drive can be used both as an individual drive and also as a dual drive.
European Patent EP 0 968 675 B1 already discloses an individual or dual drive provided in particular for articles of furniture in the hospital sector and/or the care sector. In the case of that known linear drive a worm which is carried on a motor shaft and which is in engagement with a worm gear is provided as the speed reduction gear. The worm gear is mounted rotatably on a guide body which is arranged fixedly on the threaded spindle and on which a coupling wheel is guided non-rotatably but axially displaceably. When the coupling wheel is coupled to the worm gear, the threaded spindle is driven, while in the uncoupled condition the threaded spindle is stationary. Arranged non-rotatably on the threaded spindle is a spindle nut which is connected to a stroke element and which, in dependence on the direction of rotation of the threaded spindle, is displaced in the axial direction and drives the stroke element serving to actuate the moveable furniture parts.
Such a drive mechanism has admittedly already proven its worth in practice, but such a mechanism is relatively complicated and expensive and cannot be loaded just as may be desired.